A fractal dipole antenna is capable of transmitting and/or receiving multiple frequency bands simultaneously and of increasing bandwidth of each single band due to the fractal geometry. Shaping in a fractal manner can be achieved in several ways, such shapes including gaskets, carpets, patches, trees, curves, islands, etc. The fractal structure of the antenna gives rise to the electromagnetic behavior of the antenna. Embodiments of the invention could be used for a variety of applications e.g., unmanned aircraft vehicles (UAVs), ground teams, vehicles, ships, etc.
For example, fractal dipoles can be used when a secure, robust, and accurate short range data link is needed. Fractal dipoles can be used for sensor fusion, wherein numerous sensors such as IR detectors, radars, sonars, laser range finders, etc. transmit an IRIG timing signal, orientation data such as a pointing vector and the sensor data. In this example, this data can be a combination of digital and analog data.
Examples of different embodiments of the invention can be used for transmitting and receiving data are desirable as existing structures and methods of transmitting and receiving data can be unreliable or have undesirable effects. For example, laser systems require the lasers to be aligned with one another to communicate. When the laser communication is being used on ships, maintaining laser alignment is difficult and in many cases impossible as compared to use in fixed non-moving structures. Moreover, if a ship rotates more than 180 degrees, the lasers can lose connection absent another transmitter or receiver on another side of the turning ship (even this may not be effective). Furthermore, lasers require direct line of sight to communicate. When obstacles, such as other ships or inclement weather, are located between the lasers, an optical signal can be significantly degraded or blocked entirely.
Short range secure communications can be performed using several methods, each with their own advantages and disadvantages. Laser communications are effective in providing a good quality secure communications, but require expensive tracking and pointing equipment to keep the lasers aligned, and atmospheric conditions or obstructions such as another passing ship can disrupt the link. Satellite communications in general are somewhat effective but are not efficient for short range communication. However, satellite communication signals can also be obstructed by atmospheric conditions. Satellite communication up-links are relatively secure however their down links can be easily intercepted. Transceivers using Radio frequency (RF) spectrum frequently can be a good choice for short range for a variety of reasons such as RF is not severely affected by atmospheric conditions; however, RF signals can be easily jammed or intercepted. Thus, there is a need which has not been met to provide secure short range communication with a high data capacity which is not easily jammed or intercepted and is cost-effectively utilized with existing communication systems without requiring a significant degree of maintenance and can be mass produced.
Sensor fusion is an area of study that will greatly benefit from a secure robust short range communication system. To transmit or receive data, sensor fusion requires several items of information to be known: the pointing angle of the antenna, location of the antenna, time tag of the data received and other information. If the time of data being received at multiple locations is known, then one can use triangulation to identify the location and/or bearing of the signal. However, when in a test field where there is separation from the test equipment, one must have the exact time tag for data coming across so the data can be correlated and tagged for the proper location and time.
Communication systems in accordance with different embodiments of the invention can address the above mentioned unmet needs. For example, embodiments of the invention can incorporate use of multiple sets of fractal dipole antennas in different communication systems which are operable with significant movement, e.g., rotation, of both transmitter and receiver platforms, ability to address obstructions, address high speed data requirements, can be manufactured with low cost/high volume, usable with existing communication systems, and provide secure communications.